Pulsed electromagnetic fields (PEMF) are low-energy, time-varying magnetic fields that are useful for treating therapeutically resistant problems of the musculoskeletal system. Those problems include spinal fusion, un-united fractures (or non-union fractures), failed arthrodeses, osteonecrosis, and chronic refractory tendinitis, decubitus ulcers and ligament, tendon injuries, osteoporosis, and Charcot foot. For PEMF therapy, an electromagnetic transducer coil is placed in the vicinity of the musculoskeletal injury such that pulsing the PEMF transducer produces an applied field that penetrates to the underlying bone.
For cervical PEMF therapy, an electromagnetic transducer coil is placed at the back of the patient's neck, such that the applied field from the coil penetrates to the cervical spine. One conventional approach is to use a flat oval-shaped transducer coil that is attached to a conventional cervical collar. This approach is disadvantageous because the transducer coil does not cover the entire back of the neck and the applied field does not penetrate below the vertebra at the bottom of the neck. A different approach uses a triangular-shaped transducer connected to the back of the patient's neck with a collar device.
These conventional PEMF cervical collars have an electronics circuit whose housing is separate from the rest of the collar. This housing must be attached around the patient's waist or placed atop a table next to the patient. A battery may be contained within the same housing, but the result is that the housing is heavy and cumbersome.
Until recently, prior art PEMF cervical collars have used both a primary coil and a secondary coil for providing the PEMF signal. However, a recently developed coil and drive circuit design permits the use of only a single coil, which results in a more compact and energy efficient coil. This design is described in U.S. Pat. No. 5,743,844, entitled "High Efficiency Pulsed Electromagnetic Field (PEMF) Stimulation Therapy Method and System", to Tepper et al., assigned to AMEI Technologies Inc.